Fuse



y 23, 1939- J. E. HAGENDORN ET AL 2,159,083

FUSE

Filed March 30, 1936 IN ENTORS Jodi/ nszwaoe/v Jay/v fevuae /v ATTORN EY Patented May 23, 1939 PATENT OFFICE FUSE Joseph E. Hagendorn and Jean Vervuel'en,

Hewlett, N. Y.

Application March 30, 1936, Serial No. 71,593

7 Claims.

This invention relates to fuses in general and more especially to fuse constructions which, for all practical purposes, will interfere with, if not entirely prevent, tampering with such fuses to circumvent the purpose for which intended.

It long has been an aim practically to interfere with, if not entirely prevent, tampering with fuses to circumvent the purpose for which they are intended. In view of the foregoing, it is an object of the present invention to provide a fuse that is substantially tamper-proof for all practical purposes and which will effectively prevent the use of coins or the like in the fuse socket wrongfully to divert the current from the fuse and which will 16 effectively prevent the use of wires, hair pins,

metal foil and the like in the fuse socket wrongfully to divert the current from the fuse.

It is still a further object of the present invention to provide a fuse that is substantially tam- 20 per-proof for all practical purposes, which will fit the standard out out boxes and which will facilitate the detection of any make-shift substitutes or additions wrongfully to divert the current from the fuse.

5 These and other features, capabilities and ad-- vantages of the present invention will appear from the subjoined detail description of one specific embodiment thereof illustrated in the accompanying drawing in which 30 Figure 1 is a transverse section on an enlarged scale of a fuse made according to the present in- 'vention;

Fig. 2 is a side elevation of a fuse substantially full-size with the fuse socket shown in dash and 35 dot lines;

Fig. 3 is a plan partly in section of the adapter portion of the improved fuse looking down into the socket of the adapter portion; and

Fig. 4 is a plan of the plug portion of the im- 40 proved fuse looking up at the lower end of the plug portion.

In the embodiment shown, there are provided two main sections, the adapter portion l and the plug portion 2, both preferably cast or molded 45 from a suitable insulating material, such as Bakelite or the like. The adapter portion 1, see Figs. 1 and 3, consists essentially of a socket portion composed essentially of a suitable insulating material and in form having a cylindrical 50 wall 4 provided with an outer thread 5 and an inner thread 6, the outer thread 5 preferably having a greater pitch than that of the inner thread. The cylindrical wall 4 has a base I at one end provided with a central opening 8, the outer face of the base preferably being concave and the inner face preferably plane and provided with a cylindrical extension 9 having a crown or toothed face ID at the free end thereof, see particularly Fig. 3.

To the thread 5, there is secured the shell ll 5 composed of a suitable conductive material having the flanges l2 and I3, the flange l2 engaging the inner free end of the wall 4 and the flange l3 engaging the annular face I 4 adjacent to the shoulder I5. 10

The plug portion 2 consists essentially of a head 5, an intermediate cylindrical portion I! and a diminished extension l8 provided with an external thread conforming to and engaging the inner thread 6 of the wall 4. The outer periphery of the head I6 is preferably knurled and provided with an annular recess 3 to receive the edges of the standard mica disc I9 and the anchoring annulus 20. The head 16, intermediate portion l1 and extension l8 are integral with one another being composed of some suitable insulating material such as Bakelite and chambered to form the receiving chamber for the fuse strip 2 l, which chamber consists of an outer enlarged cylindrical chambered portion 22, an intermediate bellshaped chambered portion 23 terminating in the tapered chambered portion 24.

To the plug portion 2, there are secured the ends of the fuse strip 2|, the annular flat plate or disc 25 and the metal projection 26.

The disc 25 preferably has one portion thereof secured to the annular plane face 21 of the intermediate portion I! with another portion 28 free and slightly deflected from the face 21 to form a yieldable contact finger for engagement with the 5 flange I2 of the shell H. The projection 26 is preferably molded into the diminished extension [8 extending through the axial center of the extension I8 with one end thereof secured to the fuse strip 2| by solder or the like, and the other end extending outwardly and beyond the outer central portion of the extension I8. The extension I8, see Figs. 1 and 4, has an annular recess 29 extending around the projection 26 and substantially conforming to the cylindrical extension 9 of the adapter I.

Surrounding the annular recess 29, there is formed an annular cylindrical extension 30 having an outer crown or toothed face 3|, see particularly Fig. 4. The other end of the fuse strip 2| extends through the orifice 32 formed in the intermediate portion l1 and is secured to the annular disc 25 where it engages the plane face 21 of the intermediate portion [1.

The lower end of the chambered portion 24 is preferably filled with plaster or other suitable moldable material 33 in the usual way.

In actual use, the adapter I is first secured in the metal shell 34 of the cut-out socket 35, preferably as shown to prevent accidentally removing the adapter I after it has once been inserted in the shell 34. The same is permanently secured in place by any suitable anchoring means such as the pin 36 extending in alinement with the thread of the shell ll, projecting therefrom at an angle and yieldable so as to permit securing the shell H in place in the shell 34 but cutting into the shell 34 when turning the shell ll outwardly relative to the shell 35. When the adapter l is so secured in place, contact is made between the shells H and 34 to one pole of the system to be protected and the spring finger 3i connected to the other pole of the system to be protected, extending up into alinement with the central opening 8 of the adapter After the adapter I is so anchored in the shell 3 1, the fuse plug 2 is ready to be inserted. The thread of the extension 88 will engage the thread 6 of the wall i while the plug is secured in contact forming position, where its contact ring 25 will engage the flange l2 of the shell II and the projection 26 extend through the opening 8 into engagement with the finger 31. In this position, it will be seen that the interposition of a coin or the like is impossible between the spring finger N and the fiange i2 and that any attempt to interpose a foil or wire would be frustrated in that the crown faces if] and SI will cooperate with one another to tear or shear such connector before the projector 26 can have been brought into engagement with the spring finger 31.

it is obvious that Various changes and modifications may be made to the details of construction Without departing from the general spirit of the invention as set forth in the appended claims.

We claim:

1. The combination with the socket structure of a cut-out box, of an adapter, means for anchoring said adapter in said socket structure against displacement, a fuse plug having a fuse strip, the adapter and fuse plug being composed of insulating material, a conductive shell on said adapter connected to one terminal of the system to be protected, said shell having an annular plate at one end of said adapter, there being a centrally disposed opening in said adapter, a spring finger disposed in, and secured to, said socket structure and connected to another terminal of the system to be protected and spaced from the lower face of said adapter but in alinement with said central opening, a conductive annular plate including an offset yieldable portion on said fuse plug connected to one terminal of said fuse strip, .a conductive projection on said fuse plug connected to the other terminal of said fuse strip, and cooperating threads on said fuse plug and adapter to facilitate securing the plug in said adapter and pressing the yieldable portion of said latter plate into engagement with the annular plate of said shell, and causing said projection to extend through said central opening to engage said spring finger.

2. The combination with the socket structure of a cut-out box having internal threads, of an adapter having external threads engaging said internal threads, a pin in alinement with said external threads and projecting outwardly therefrom to bite into the internal threads if the adapter is turned to withdraw the adapter from the socket structure, a fuse plug having a fuse strip, the adapter and fuse plug being composed of insulating material, a conductive shell on said adapter connected to one terminal of the system to be protected, said shell having an annular plate at one end of said adapter, there being a centrally disposed opening in said adapter, a spring finger disposed in, and secured to, said socket structure and connected to another terminal of the system to be protected and spaced from the lower face of said adapter but in alinement with said central opening, a conductive annular plate including an offset yieldable portion on said fuse plug connected to one terminal of said fuse strip, a conductive projection on said fuse plug connected to the other terminal of said fuse strip, and cooperating threads on said fuse plug and adapter to facilitate securing the plug in said adapter and pressing the yieldable portion of said latter plate into engagement with the yieldable portion of said shell, and causing said projection to extend through said central opening to engage said spring finger.

3. The combination with the socket structure of a cut-out box, of an adapter, means for anchoring said adapter in said socket structure against displacement, a fuse plug having a fuse strip, the adapter and fuse plug being composed of insulating material, a conductive shell on said adapter connected to one terminal of the system to be protected, said shell having an annular plate at one end of said adapter, there being a centrally disposed opening in said adapter, a spring finger disposed and secured in said socket structure and connected to another terminal of the system to be protected and spaced from the lower face of said adapter but in alinement with said central opening, a conductive plate including an offset yieldable portion on said fuse plug connected to one terminal of said fuse strip, a conductive projection on said fuse plug connected to the other terminal of said fuse strip, cooperating threads on said fuse plug and adapter to facilitate securing the plug in said adapter and pressing the yieldable portion of said latter plate into engagement with the annular plate of said shell, and causing said projection to extend through said central opening to engage said spring finger, a cylindrical projection on said plug concentric with and spaced from said conductive projection, and a cylindrical projection on said adapter conforming to the space between said first cylindrical projection and said conductive projection snugly to fit into such space when the fuse plug is screwed into said adapter.

4. The combination with the socket structure of a cut-out box, of an adapter, means for anchoring said adapter in said socket structure against displacement, a fuse plug having a fuse strip, the adapter and fuse plug being composed of insulating material, a conductive shell on said adapter connected to one terminal of the system to be protected, said shell having an annular plate at one end of said adapter, there being a centrally disposed opening in said adapter, a spring finger secured to said socket structure and connected to another terminal of the system to be protected and spaced from the lower face of said adapter but in alinement with said central opening, a conductive annular plate including an offset yieldable portion on said fuse plug connected to one terminal of said fuse strip, a conductive projection on said fuse plug connected to the other terminal of said fuse strip, and coopcrating threads on said fuse plug and adapter to facilitate securing the plug in said adapter and pressing the yieldable portion of said latter plate into engagement with the annular plate of said shell and said projection to extend through said central opening to engage said spring finger, a portion of said plate being yieldable and spaced from said plug to provide a yieldable contact for engagement with said shell.

5. The combination with the socket structure of a cut-out box, of an adapter, means for anchoring said adapter in said socket structure against displacement, a fuse plug having a fuse strip, the adapter and fuse plug being composed of insulating material, a conductive shell on said adapter connected to one terminal of the system to be protected, there'being a centrally disposed opening in said adapter, a spring finger in said socket structure connected to another terminal of the system to be protected and spaced from the lower face of said adapter but in alinernent with said central opening, a conductive disc on said fuse plug connected to one terminal of said fuse strip, a conductive projection on said fuse plug connected to the other terminal of said fuse strip, cooperating threads on said fuse plug and adapter to facilitate securing the plug in said adapter and positioning said disc in engagement with said shell, and said projection to extend through said central opening to engage said spring finger, a cylindrical projection on said plug concentric with and spaced from said con ductive projection, a cylindrical projection on said adapter conforming to the space between said first cylindrical projection and said conductive projection snugly to fit into such space when the fuse plug is screwed into said adapter, and teeth on the free plane faces of said cylindrical projections.

6. The combination with the socket structure of a cut-out box, of an adapter, a fuse plug having a fuse strip, the adapter and fuse plug being composed of insulating material, a conductive shell on said adapter connected to one terminal of the system to be protected, there being a centrally disposed opening in said adapter, a finger in said socket structure connected to another terminal of the system to be protected and in alinement with said central opening, a conductive disc on said fuse plug connected to one terminal of said fuse strip, a conductive projection on said fuse plug connected to the other terminal of said fuse strip, cooperating threads on said fuse plug and adapter to facilitate securing the plug in said adapter and positioning said disc in engagement with said shell, and said projection to engage said finger, a cylindrical projection on said plug concentric with and spaced from said conductive projection, a cylindrical projection on said adapter conforming to the space between said first cylindrical projection and said conductive projection snugly to fit into such space when the fuse plug is screwed into said adapter, and teeth on the free plane faces of said cylindrical projections.

7. The combination with the socket structure of a cut-out box, of an adapter, a fuse plug having a fuse strip, the adapter and fuse plug being composed of insulating material, a conductive shell on said adapter connected to one terminal of the system to be protected, there being a centrally disposed opening in said adapter, means in said socket structure connected to another terminal of the system to be protected, a conductive disc on said fuse plug connected to one terminal of said fuse strip, a conductive projection on said fuse plug connected to the other terminal of said fuse strip, cooperating threads on said fuse plug and adapter to facilitate securing the plug in said adapter and positioning said disc in engagement With said shell, and said projection to engage said means, a cylindrical projection on said plug concentric With and spaced from said conductive projection, a cylindrical projection on said adapter conforming to the space between said first cylindrical projection and said conductive projection snugly to fit into such space when the fuse plug is screwed into said adapter, and teeth on the free plane faces of said cylindrical projections.

JOSEPH E. HAGENDORN. JEAN VERVUEREN. 

